Nmap is well known as a free and open source network exploration and security auditing app. While it may be an invaluable tool for system administrators, it has also turned out to be a very useful piece of software for scanning the web and extracting information from it.

Earlier this year the Nmap Security Scanner was used to retrieve the icon of the top one million websites. Of those million, 328,427 returned a unique icon, and only 288,945 turned out to be images that could be used. Still, that’s a substantial number of icons.

Nmap correlated each icon with the reach of a particular site. The resulting visualization renders each icon at a size corresponding to that reach. As Nmap explain:

The area of each icon is proportional to the sum of the reach of all sites using that icon. When both a bare domain name and its “www.” counterpart used the same icon, only one of them was counted. The smallest icons–those corresponding to sites with approximately 0.0001% reach–are scaled to 16×16 pixels. The largest icon (Google) is 11,936 x 11,936 pixels, and the whole diagram is 37,440 x 37,440.

The image below is just a summary of the image map and top sites within it. If you want to use the interactive version just visit http://nmap.org/favicon/

Nmap admit that there are some data errors in the map due to certain sites timing out. But for the most part the visualization gives a pretty good representation of where the power lies on the web at the moment.